Actin protects mammalian eggs against chromosome segregation errors

Aneuploidy is a cellular condition characterized by the gain or loss of specific chromosomes. This can arise from chromosome segregation problems during cell division in the germ line (a process called meiosis), and is the main cause of age-related female infertility, spontaneous miscarriage, and developmental disorders in humans. To segregate chromosomes, cells rely on a spindle-shaped structure made up of filaments called microtubules. On page 772 of this issue, Mogessie and Schuh (1) show that another cytoskeleton filament—actin—can be found in close association with microtubules in the spindle and promotes chromosome segregation fidelity during meiosis in mammalian oocytes